# Update and delete rows

UPDATE and DELETE change rows immediately. Use a transaction when several changes should succeed or roll back together.

This example reduces the stock of one item and removes an item that has no stock.

## Prepare sample data

```sql
CREATE TABLE stock(id INTEGER PRIMARY KEY, quantity INTEGER);
INSERT INTO stock VALUES (1, 5), (2, 0);
```

## Change matching rows

```sql
BEGIN;
UPDATE stock SET quantity = quantity - 1 WHERE id = 1;
DELETE FROM stock WHERE quantity = 0;
COMMIT;
```

`WHERE` determines which rows change. Omitting it would update or delete every row. `COMMIT` keeps the transaction's changes; use `ROLLBACK` instead to discard them.

## Verify the result

```sql
SELECT id, quantity
FROM stock
ORDER BY id
FORMAT csv;
```

```text
1,4
```

To read changed rows directly from a write, use its `RETURNING` clause. See [`UPDATE`](https://coordinatordb.com/docs/reference/statements/update), [`DELETE`](https://coordinatordb.com/docs/reference/statements/delete) and [transactions](https://coordinatordb.com/docs/concepts/features/operations/insert/transactions).